Nottingham is pretty "clean" and neutral, so you won't get the same flavor profile. Normally, liquid yeast without a starter can take up to 72 hours to start. If you didn't use a starter and used older yeast, you probably can double that time. I'd wait the 72 hours, and see if it starts. I'd be scared to go longer than though, although you probably could if no action starts as long as you were sanitary.
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